Background

Plant glycine-rich proteins are categorized into several classes based on their protein structures. The glycine-rich RNA binding proteins (GRPs) are members of class IV subfamily possessing N-terminus RNA-recognition motifs (RRMs) and proposed to be involved in post-transcriptional regulation of its target transcripts. GRPs are involved in developmental process and cellular stress responses, but the molecular mechanisms underlying these regulations are still elusive.

Results

Here, we report the functional characterization of rice GLYCINE-RICH PROTEIN 3 (OsGRP3) and its physiological roles in drought stress response. Both drought stress and ABA induce the expression of OsGRP3. Transgenic plants overexpressing OsGRP3 (OsGRP3^OE) exhibited tolerance while knock-down plants (OsGRP3^KD) were susceptible to drought compared to the non-transgenic control. In vivo, subcellular localization analysis revealed that OsGRP3-GFP was transported from cytoplasm/nucleus into cytoplasmic foci following exposure to ABA and mannitol treatments. Comparative transcriptomic analysis between OsGRP3^OE and OsGRP3^KD plants suggests that OsGRP3 is involved in the regulation of the ROS related genes. RNA-immunoprecipitation analysis revealed the associations of OsGRP3 with PATHOGENESIS RELATED GENE 5 (PR5), METALLOTHIONEIN 1d (MT1d), 4,5-DOPA-DIOXYGENASE (DOPA), and LIPOXYGENASE (LOX) transcripts. The half-life analysis showed that PR5 transcripts decayed slower in OsGRP3^OE but faster in OsGRP3^KD, while MT1d and LOX transcripts decayed faster in OsGRP3^OE but slower in OsGRP3^KD plants. H₂O₂ accumulation was reduced in OsGRP3^OE and increased in OsGRP3^KD plants compared to non-transgenic plants (NT) under drought stress.

Conclusion

OsGRP3 plays a positive regulator in rice drought tolerance and modulates the transcript level and mRNA stability of stress-responsive genes, including ROS-related genes. Moreover, OsGRP3 contributes to the reduction of ROS accumulation during drought stress. Our results suggested that OsGRP3 alleviates ROS accumulation by regulating ROS-related genes’ mRNA stability under drought stress, which confers drought tolerance.

中文翻译：

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水稻中富含甘氨酸的蛋白质3通过调节ROS清除相关基因的mRNA稳定性赋予抗旱性

背景

富含植物甘氨酸的蛋白质根据其蛋白质结构分为几类。富含甘氨酸的RNA结合蛋白（GRP）是具有N端RNA识别基序（RRM）的IV类亚家族的成员，并提议参与其目标转录本的转录后调控。GRPs参与发育过程和细胞应激反应，但这些法规所依据的分子机制仍然难以捉摸。

结果

在这里，我们报告水稻富含甘氨酸的蛋白质3（OsGRP3）的功能表征及其在干旱胁迫响应中的生理作用。干旱和ABA均可诱导OsGRP3表达。与非转基因对照相比，过表达OsGRP3的转基因植物（OsGRP3 ^OE）表现出耐受性，而敲除型植物（OsGRP3 ^KD）对干旱敏感。在体内，亚细胞定位分析表明，暴露于ABA和甘露醇处理后，OsGRP3-GFP从细胞质/细胞核转移到细胞质灶中。OsGRP3 ^OE之间的比较转录组学分析和OsGRP3 ^KD植物表明，OsGRP3参与了ROS相关基因的调控。RNA免疫沉淀分析揭示了OsGRP3与光致病相关基因5（PR5），金属硫蛋白1d（MT1d），4,5-DOPA-DIOXYGENASE（DOPA）和LIPOXYGENASE（LOX）转录本的关联。半衰期分析表明，PR5转录本在OsGRP3 ^OE中的衰减较慢，而在OsGRP3 ^KD中的衰减较快，而MT1d和LOX的衰减更快转录本在OsGRP3 ^OE中衰减较快，而在OsGRP3 ^KD植物中则较慢。与干旱胁迫下的非转基因植物（NT）相比，OsGRP3 ^OE中的H ₂ O ₂积累减少，而OsGRP3 ^KD植物中的H ₂ O ₂积累增加。

结论

OsGRP3在水稻抗旱性中发挥正调控作用，并调节胁迫响应基因（包括ROS相关基因）的转录水平和mRNA稳定性。此外，OsGRP3有助于减少干旱胁迫期间ROS的积累。我们的研究结果表明，OsGRP3通过调节干旱胁迫下ROS相关基因的mRNA稳定性来减轻ROS积累，从而赋予了其耐旱性。